The ‘a‘o is a medium-sized shearwater with a glossy black top, a white bottom, and a black bill that is sharply hooked at the tip. Its claws are well adapted for burrow excavation and climbing. They feed primarily on squid and fish.
The ‘a‘o was once abundant on all main Hawaiian islands. Today, they only nest in the mountainous terrain between 500 to 2,300 feet on Kaua‘i. This seabird was reported to be in danger of extinction by the 1930s. The introduction of the mongooses, rats, cats, dogs, and pigs have played a primary role in the reduction of ground nesting seabirds such as the ‘a‘o and the ‘ua‘u (Hawaiian dark-rumped petrel).
A second threat to the ‘a‘o is its attraction to light. Increasing urbanization and the accompanying manmade lighting have resulted in substantial problems for fledgling shearwaters during their first flight to the ocean from their nesting grounds. When attracted to manmade lights, fledglings become confused and may suffer temporary night blindness. They often fly into utility wires, poles, trees, and buildings and fall to the ground. Between 1978 and 2007, more than 30,000 ‘a‘o fell on Kaua‘i’s highways, athletic fields, and hotel grounds.
Kīlauea Point is trying to increase the breeding population on the refuge by installing artificial burrows and a sound system that broadcasts the sound of a large colony of ‘a‘o calls throughout the night. Overall, the ‘a‘o population is declining and Kaua‘i has greater than 80 percent of the entire population. The refuge is currently the only place where a colony is protected in perpetuity and there is active predator control.
‘A‘o is a bird of the open tropical seas and offshore waters near breeding grounds. Their burrows are used year after year and usually by the same pair of birds. Although they are capable of climbing shrubs and trees before taking flight, ‘a‘o need an open downhill flight path to become airborne. Nesters begin arriving to Kīlauea Point at the beginning of April. ‘A‘o are synchronous breeders that will lay an egg in late May or early June. During their 9-month breeding season, they live in burrows under ferns on forested mountain slopes.
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The Mōlī or Laysan albatross may spend years over the open ocean without ever touching land!